CN103206668A - Free-form surface lens for projection-type light emitting diode (LED) automobile dipped headlight - Google Patents

Free-form surface lens for projection-type light emitting diode (LED) automobile dipped headlight Download PDF

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CN103206668A
CN103206668A CN2013100217466A CN201310021746A CN103206668A CN 103206668 A CN103206668 A CN 103206668A CN 2013100217466 A CN2013100217466 A CN 2013100217466A CN 201310021746 A CN201310021746 A CN 201310021746A CN 103206668 A CN103206668 A CN 103206668A
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form surface
free
light
theta
lens
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王洪
王丽君
陈赞吉
葛鹏
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South China University of Technology SCUT
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South China University of Technology SCUT
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Abstract

The invention provides a free-form surface lens for a projection-type light emitting diode (LED) automobile dipped headlight. The free-form surface lens is composed of two surfaces, wherein the first surface is a circular plane, and the second surface is a free-form surface; and a normal vector of a point on the free-form surface is obtained through a refraction law, a tangent plane is obtained through the normal vector, a coordinate of the point on the free-form surface is obtained by determining an intersection point of the tangent plane and a light ray, the light ray is obtained by refracting the next point through the first surface of the lens to enter into the free-form surface, the next point is obtained by intersecting the tangent plane of the last point and a straight line where the normal sector of the next point is positioned, coordinates of points of a curve on the free-form surface on a coordinate plane are obtained through iteration, and the obtained coordinates of the points are fitted into a curve and then rotated around a Z-axis by 360 degrees to obtain the final lens free-form surface. According to the free-form surface lens, trends and distribution of light rays are controlled through the lens free-form surface, so that light areas of the lens can meet the requirement of national standards for light distribution and illumination of the automobile dipped headlight.

Description

The free-form surface lens that is used for projection-type LED automobile dipped headlight
Technical field
The invention belongs to the LED lighting technical field, be specifically related to a kind of free-form surface lens of projection-type LED automobile dipped headlight.
Background technology
Traditional headlamp light source has incandescent lamp, Halogen lamp LED and high-intensity gas discharge lamp (HID), and incandescent lamp and Halogen lamp LED are short service life, though HID is longer service life, energy consumption is very big.And led light source has long, the incomparable advantages of conventional light source such as volume is little, energy-conserving and environment-protective, the response time is short, design freedom is big of life-span, therefore become car headlamp the 4th generation light source.
Headlamp is throw light on when the night running light fixture of road ahead of automobile, and its luminous intensity distribution design is the key factor that influences automotive lighting quality and effect.In the design of car headlamp, the luminous intensity distribution figure of the car headlamp of standard GB 25991-2010 stipulates that purpose is to prevent that car headlamp from disturbing the opposite to sail vehicle and cause traffic accident.Concerning dipped headlights, illuminated area generation one horizontal line that requirement 25m before car light is far away and horizontal line right side be 15 ° "cut-off"line upwards.The lower beam illumination face can be divided into four zones: ZONE I (I district) satisfies the marginal illumination demand in the scope of whole road surface for to have bigger diffusion, the good substrate luminous intensity distribution of the uniformity; ZONE II, III, IV are to have that light energy is comparatively concentrated, range center luminous intensity distribution far away, satisfy this track and road surface, the right (be example with vehicle right lateral standard) lighting demand at a distance.In I, II in III and the IV district, should not have the transverse illumination that influences good visibility and changes.
Early stage LED projection-type system adopts a plurality of led light sources, each led light source has separate optical system, it is big that this optical system takies volume, be unfavorable for heat radiation, energy loss is serious, and the aplanatic non-spherical lens of the general employing of lens, light evenly can't be dispersed, it is less that fringe region luminous energy is distributed.
Summary of the invention
The present invention be directed to traditional LED automobile dipped headlight with non-spherical lens during as lens, distribution of light and move towards control rational drawback inadequately, propose a kind of can reasonable distribution light and the free-form surface lens that is used for projection-type LED automobile dipped headlight of luminous energy, improved the efficiency of light energy utilization, increase field range, and met the light distribution requirements of automobile dipped headlight.
The present invention is achieved through the following technical solutions:
Projection-type LED automobile dipped headlight free-form surface lens is made by transparent material, and transparent material is PMMA.Free-form surface lens comprises two faces, and first is plane (plane of incidence), and second is free form surface (exit facet).The shape of this free form surface is determined by following method:
The free-form surface lens that is used for projection-type LED automobile dipped headlight is characterized in that this free-form surface lens made by transparent material, and free-form surface lens is made of two faces, i.e. the plane of incidence and exit facet, and wherein the plane of incidence is circular flat, exit facet is free form surface.
Further, the shape of described free form surface is determined as follows:
Second focus with the ellipsoid reflector of projection-type LED automobile dipped headlight is that the origin of coordinates is set up rectangular coordinate system, be XOY plane with the plane crossing initial point and be parallel to the free-form surface lens plane of incidence, be the Z axle with described free-form surface lens thickness direction (namely perpendicular to the plane of incidence) place straight line, choosing a straight line of crossing initial point at XOY plane is X-axis, since this free-form surface lens be with the Z axle serve as the rotation axisymmetric, so for the terseness of describing, following calculating is chosen in the XOZ plane to be carried out;
Target illumination face and described origin of coordinates distance are H, and the target illumination face is divided into I district, II district, III district and IV district according to the national standard (GB25991-2010) of vapour automobile-used LED headlamp, there is corresponding illumination requirement value in each zone, the III district is glare area, its maximal illumination can not surpass 0.7lx, and the light that second focus of ellipsoid reflector is sent is according to angle θ 1, θ 2, θ 3Be divided into 3 parts and project other 3 zones except the III district on the illuminated area respectively;
Light according to the given whole illuminated area of request of national standard is distributed as P 0, the central light strength of light source is I 0, the light and the Z-direction angle that send from ellipsoid reflector second focus are θ 1That part of light incide that to be radiated at from illuminated area centre distance behind the lens be r 1The position, with the z axis angle less than θ 1That part of light behind lens, be radiated at the position of illuminated area and illuminated area centre distance less than r 1, with the angle θ of first's light correspondence 1Be divided into i part, each θ 1In radius r 1On also be divided into i part accordingly, the corresponding like this array θ that obtained 1(i) and array r 1(i), the conservation of energy expression formula of the illumination on first area emergent light and the illuminated area is so:
2 π ∫ 0 θ 1 ( i ) I 0 cos θ sin θ · dθ = 2 π ∫ 0 r 1 ( i ) P 0 · r · dr - - - ( 1 ) ;
In like manner, light and the Z-direction angle that sends from ellipsoid reflector second focus is θ 1~θ 2Between that part of light incide that to be radiated at from illuminated area centre distance behind the lens be r 1~r 2The position, this part light is divided into j part, corresponding each angle also is divided into j part, the corresponding like this array θ that obtained on radius 2(j) and array r 2(j), then should the zone emergent light and illuminated area on the conservation of energy expression formula of illumination be:
2 π ∫ θ 1 θ 2 I 0 cos θ sin θ · dθ = 2 π ∫ r 1 r 2 ( j ) P 0 · r · dr - - - ( 2 ) ;
In like manner, light and the Z-direction angle that sends from ellipsoid reflector second focus is θ 2~θ 3Between that part of light incide that to be radiated at from illuminated area centre distance behind the lens be r 2~r 3The position, this part light is divided into k part, corresponding each angle also is divided into k part on radius, so just obtained array θ 3(k) and array r 3(k), can the zone emergent light and illuminated area on the conservation of energy expression formula of illumination be
2 π ∫ θ 2 θ 3 ( k ) I 0 cos θ sin θ · dθ = 2 π ∫ r 2 r 3 ( k ) P 0 · r · dr - - - ( 3 ) ;
By above-mentioned three expression formulas, the relational expression that obtains respectively between each zone radius and the emergent light angle is as follows:
r 1 ( i ) = I 0 P 0 · sin 2 θ 1 ( i ) - - - ( 4 )
r 2 ( j ) = I 0 P 0 · ( sin 2 θ 2 ( j ) - sin 2 θ 1 ) + r 1 2 - - - ( 5 )
r 3 ( k ) = I 0 P 0 · ( sin 2 θ 3 ( k ) - sin 2 θ 2 ) + r 2 2 - - - ( 6 ) ;
Drawn the normal vector of putting on the described free form surface by the law of refraction, utilize this normal vector to obtain the section, by determining that section and the intersection point through inciding the light on the free form surface after first refraction of lens that descends any obtain the coordinate of putting on the free form surface, obtained down a bit with the straight line at the normal vector place of descending any is crossing by more preceding section, obtain the coordinate of the curve each point of free form surface on coordinate plane by iteration, after the point coordinates that obtains fitted to curve, namely obtain final lens free form surface for 360 ° around the rotation of Z axle.
Arrange the free-form surface lens plane of incidence and ellipsoid reflector second focus apart from f=10mm, then the free-form surface lens plane of incidence has according to the law of refraction:
sin θ sin θ ′ = n ′ n - - - ( 7 )
Light incides the free form surface medium from air, and the refractive index of air is n=1, and free-form surface lens uses material PMMA to make refractive index n '=1.4935; θ is the angle (i.e. light and the Z-direction angle that sends from ellipsoid reflector second focus) of incident ray, θ ' is the angle (i.e. light and Z-direction angle through reflecting behind the free-form surface lens plane of incidence) of refracted ray, the intersecting point coordinate value of incident ray and the free-form surface lens plane of incidence is (ftan (θ), f), and the slope value of refracted ray is cot (θ '), utilizes point slope form can obtain the equation of refracted ray;
Light reflects again when the exit facet of process free-form surface lens, and the vector form of the law of refraction is expressed as
[ 1 + n 2 - 2 n ( Out → · In → ) ] 1 / 2 · N → = Out → - n · In → - - - ( 8 ) ,
Wherein: n is the free form surface medium refraction index,
Figure BDA00002754550000042
Be the incident ray unit vector, Be the emergent ray unit vector,
Figure BDA00002754550000044
Be the unit normal vector of free form surface at the light incidence point;
When definite free form surface shape, at first determine an initial point, this initial point operated by rotary motion on the Z axle, numerical values recited be free-form surface lens thickness h and the lens plane of incidence and ellipsoid reflector second focus apart from f with, be initial point coordinate for (0, h+f).If the intersection point A coordinate of incident ray and the free-form surface lens plane of incidence be (x ', f), the point B coordinate that light shines on the free form surface after reflecting through the plane of incidence is (x, z), the point C coordinate that light projects on the illuminated area after reflecting through lens is (r, H), H=25m wherein, r is determined by formula (4), (5), (6) according to law of conservation of energy; So can obtain incident ray
Figure BDA00002754550000045
With emergent ray
Figure BDA00002754550000046
Unit vector, the recycling law of refraction (formula 8) namely obtains the normal vector that B is ordered, thereby determines the section of this point, thus the more following of free form surface determined with any ray intersection through inciding on the free form surface after the plane of incidence refraction down in this section; Obtained down a bit with the straight line at the normal vector place of descending any is crossing by more preceding section, namely obtain the coordinate of each point by the machine iteration; After the point coordinates that obtains fitted to curve, namely obtain final lens free form surface for 360 ° around the rotation of Z axle.
The present invention has following beneficial effect: the lens that the invention provides a kind of projection-type LED automobile dipped headlight, the free form surface of scioptics is controlled trend and the distribution of light, makes its field of illumination meet national standard to light distribution and the illumination requirement of automobile dipped headlight.The present invention can reasonable distribution light and the free-form surface lens that is used for projection-type LED automobile dipped headlight of luminous energy, has improved the efficiency of light energy utilization, has increased field range.
Description of drawings
Fig. 1 is the light zoning figure during to illuminated area for the ray cast of coming out from ellipsoid second focus in the embodiment.
Fig. 2 is the coordinate profiles figure of lens in the embodiment.
Fig. 3 is the front view of lens in the embodiment.
Fig. 4 is the side view of lens in the embodiment.
Fig. 5 is the 3 dimensional drawing of lens in the embodiment.
Fig. 6 is the front view of projection-type dipped headlights system in the embodiment.
Fig. 7 is the side view of projection-type dipped headlights system in the embodiment.
The specific embodiment
Below in conjunction with accompanying drawing and example enforcement of the present invention is described further, but enforcement of the present invention is not limited thereto.
(1) determine primary condition and the target illumination zone divided, the result as shown in Figure 1.
Fig. 6, Fig. 7 are respectively front view and the side view of projection-type LED dipped headlights system, and projection-type LED dipped headlights system comprises led light source 201, ellipsoid reflector 202, baffle plate 203 and free-form surface lens 204.According to the optical characteristics of ellipsoid reflector, led light source is placed on first focus of ellipsoid reflector in the mode vertical with optical axis; Baffle plate is placed on second focus of ellipsoid reflector, and overlaps with the focus of free-form surface lens.Because the light that light source sends can be assembled at the second focus place of ellipsoid reflector after reflection, thereby can will regard a spot light outgoing as from the light of the second focus outgoing.Second focus with the ellipsoid reflector of projection-type LED automobile dipped headlight is that the origin of coordinates is set up rectangular coordinate system, is the Z axle with described free-form surface lens thickness direction (perpendicular to first face) place straight line, is X-axis with the straight line parallel with described circular flat.
At first the distance of target illumination face and this dipped beam system is 25m, according to GB25991-2010, the target illumination zone is divided into 4 districts (I district, II district, III district, IV district), the III district is glare area, its brightness value is no more than 0.7lx, will be divided into other 3 zones except the III district that 3 parts project the target illumination zone respectively through the light of outgoing after the ellipsoid reflector reflection.According to the Illumination Distribution of field of illumination, the length of field of illumination is divided into 3 parts, because dipped beam requires its zone length to reach 3960mm, thereby our radius of maximum is set to r 3=4m, first's radius is made as r 1=500mm, the second portion radius is set to r 2=2250mm; Because being approximately lambert's body, the optical field distribution of LED distributes, unsuitable excessive according to the size of dim head lights lamp again so the angle that can be utilized through the reflector light reflected is not 90 °, thereby we select to utilize light angle to be approximately 65 °.The light of these 65 degree is divided into 3 parts, θ 1, θ 2, θ 3With 0~θ 1, θ 1~θ 2, θ 2~θ 3Light be divided into 100 parts, so just formed θ 1(100), θ 2(100), θ 3(100) array; Then all light are projected the correspondence position of field of illumination respectively.
(2) set up through the energy behind the ellipsoid reflector and the relational equation that projects the energy of illuminated area according to law of conservation of energy
If the gross energy of light source is 100lm, then given light is distributed as P 0=3.9789lx, the central light strength of light source are I 0=31.8310cd, the consideration direction is θ 1The position of the illuminated area that incides of light be r 1, with axis angle less than θ 1The position coordinates of light incident also less than r 1, with the light θ of first 1Be divided into i part, corresponding each θ 1In radius r 1On also be divided into i part, so just obtained array θ 1(i) and r 1(i), the conservation of energy expression formula of the illumination on first area emergent light and the illuminated area is so:
2 π ∫ 0 θ 1 ( i ) I 0 cos θ sin θ · dθ = 2 π ∫ 0 r 1 ( i ) P 0 · r · dr - - - ( 9 )
Angle is θ 1~θ 2Between the light position of inciding illuminated area be r 1~r 2, this part light is divided into j part, corresponding each angle also is divided into j part on radius, so just obtained array θ 2(j) and r 2(j), then should the zone emergent light and illuminated area on the conservation of energy expression formula of illumination be:
2 π ∫ θ 1 θ 2 I 0 cos θ sin θ · dθ = 2 π ∫ r 1 r 2 ( j ) P 0 · r · dr - - - ( 10 )
In like manner, angle is θ 2~θ 3Between the light position of inciding illuminated area be r 2~r 3, this part light is divided into k part, corresponding each angle also is divided into k part on radius, so just obtained array θ 3(k) and r 3(k), can the zone emergent light and illuminated area on the conservation of energy expression formula of illumination be
2 π ∫ θ 2 θ 3 ( k ) I 0 cos θ sin θ · dθ = 2 π ∫ r 2 r 3 ( k ) P 0 · r · dr - - - ( 11 )
By these three expression formulas, the relational expression that can obtain respectively between each zone radius and the emergent light angle is as follows:
r 1 ( i ) = I 0 P 0 · sin 2 θ 1 ( i ) - - - ( 12 )
r 2 ( j ) = I 0 P 0 · ( sin 2 θ 2 ( j ) - sin 2 θ 1 ) + r 1 2 - - - ( 13 )
r 3 ( k ) = I 0 P 0 · ( sin 2 θ 3 ( k ) - sin 2 θ 2 ) + r 2 2 - - - ( 14 )
With r 1=500mm, r 2=2250mm brings in above-mentioned 3 formulas, obtains r respectively 1Sequence, r 2Sequence, r 3Sequence.
(3) obtain the normal vector of putting on the described curved surface by the law of refraction, utilize this normal vector to try to achieve the section, obtain the coordinate of putting on the curve by asking section and the intersection point through inciding the light on the free form surface after first refraction that descends a bit.
Arrange the free-form surface lens plane of incidence and ellipsoid reflector second focus apart from f=10mm, then the free-form surface lens plane of incidence has according to the law of refraction:
sin θ sin θ ′ = n ′ n - - - ( 15 )
Light incides the free form surface medium from air, and the refractive index of air is n=1, and free-form surface lens uses material PMMA to make refractive index n '=1.4935.If the intersection point A coordinate of incident ray and the free-form surface lens plane of incidence be (x ', f), the point B coordinate that light shines on the free form surface after reflecting through the plane of incidence is (x, z), light through project after the lens refractions on the illuminated area some C coordinate for (r, H), A point coordinates value can be tried to achieve and is (ftan (θ), f), and the slope value of refracted ray AB is cot (θ '), utilizes point slope form can obtain the linear equation of AB.
Light reflects through second of free-form surface lens the time, and the vector form of the law of refraction can be expressed as
[ 1 + n 2 - 2 n ( Out → · In → ) ] 1 / 2 · N → = Out → - n · In → - - - ( 16 )
Wherein: n is the free form surface medium refraction index,
Figure BDA00002754550000072
Be the incident ray unit vector, Be the emergent ray unit vector,
Figure BDA00002754550000074
Be the unit normal vector of free form surface at the light incidence point.
When calculating free form surface face type, at first determine the initial point (0.0215 of a calculating, 0.01), if the some B coordinate that light incides on the free form surface after through first refraction is (x, z), light through project after the lens refractions on the screen some C coordinate for (r, H), H=25m wherein, r is determined by formula (12), (13), (14) according to law of conservation of energy.So, incident ray With emergent ray
Figure BDA00002754550000076
Unit vector all can try to achieve, the recycling law of refraction (formula 16) can obtain the normal vector that B is ordered, thereby determine the section of this point, thereby the more following of free form surface determined with the ray intersection through inciding after first refraction on the free form surface that descends any in this section.Obtained down a bit with the straight line at the normal vector place of descending any is crossing by more preceding section, can obtain the coordinate of each point by computer iterations.Thereby determined the coordinate of each point on the free form surface.
(4) point that utilizes mechanical modeling software to obtain fits to curved surface
As Fig. 2, the point coordinates that obtains fitted to curve after, namely obtain final lens free form surface for 360 ° around the rotation of Z axle.Fig. 3~5 are respectively free-form surface lens front view, side view, stereogram, and free-form surface lens comprises the plane of incidence 101, free form surface 102.
After adopting technique scheme, can reasonably control distribution of light and trend, make light type field range wider, spot zone is remarkable, good illumination effect.

Claims (3)

1. the free-form surface lens that is used for projection-type LED automobile dipped headlight, it is characterized in that this free-form surface lens made by transparent material, free-form surface lens is made of two faces, i.e. the plane of incidence and exit facet, wherein the plane of incidence is circular flat, and exit facet is free form surface.
2. the free-form surface lens for projection-type LED automobile dipped headlight according to claim 1 is characterized in that, the shape of described free form surface is determined as follows:
Second focus with the ellipsoid reflector of projection-type LED automobile dipped headlight is that the origin of coordinates is set up rectangular coordinate system, be XOY plane with the plane crossing initial point and be parallel to the free-form surface lens plane of incidence, be the Z axle with described free-form surface lens thickness direction place straight line, choosing a straight line of crossing initial point at XOY plane is X-axis, since this free-form surface lens be with the Z axle serve as the rotation axisymmetric, so for the terseness of describing, following calculating is chosen in the XOZ plane to be carried out;
Target illumination face and described origin of coordinates distance are H, and the target illumination face is divided into I district, II district, III district and IV district according to the standard GB 25991-2010 of vapour automobile-used LED headlamp, there is corresponding illumination requirement value in each zone, the III district is glare area, its maximal illumination can not surpass 0.7lx, and the light that second focus of ellipsoid reflector is sent is according to angle θ 1, θ 2, θ 3Be divided into 3 parts and project other 3 zones except the III district on the illuminated area respectively;
Light according to the given whole illuminated area of described request of national standard is distributed as P 0, the central light strength of light source is I 0, the light and the Z-direction angle that send from ellipsoid reflector second focus are θ 1That part of light incide that to be radiated at from illuminated area centre distance behind the lens be r 1The position, with the z axis angle less than θ 1That part of light behind lens, be radiated at the position of illuminated area and illuminated area centre distance less than r 1, with the angle θ of first's light correspondence 1Be divided into i part, each θ 1In radius r 1On also be divided into i part accordingly, the corresponding like this array θ that obtained 1(i) and array r 1(i), the conservation of energy expression formula of the illumination on first area emergent light and the illuminated area is so:
2 π ∫ 0 θ 1 ( i ) I 0 cos θ sin θ · dθ = 2 π ∫ 0 r 1 ( i ) P 0 · r · dr - - - ( 1 ) ;
In like manner, light and the Z-direction angle that sends from ellipsoid reflector second focus is θ 1~θ 2Between that part of light incide that to be radiated at from illuminated area centre distance behind the lens be r 1~r 2The position, this part light is divided into j part, corresponding each angle also is divided into j part, the corresponding like this array θ that obtained on radius 2(j) and array r 2(j), then should the zone emergent light and illuminated area on the conservation of energy expression formula of illumination be:
2 π ∫ θ 1 θ 2 I 0 cos θ sin θ · dθ = 2 π ∫ r 1 r 2 ( j ) P 0 · r · dr - - - ( 2 ) ;
In like manner, light and the Z-direction angle that sends from ellipsoid reflector second focus is θ 2~θ 3Between that part of light incide that to be radiated at from illuminated area centre distance behind the lens be r 2~r 3The position, this part light is divided into k part, corresponding each angle also is divided into k part on radius, so just obtained array θ 3(k) and array r 3(k), can the zone emergent light and illuminated area on the conservation of energy expression formula of illumination be
2 π ∫ θ 2 θ 3 ( k ) I 0 cos θ sin θ · dθ = 2 π ∫ r 2 r 3 ( k ) P 0 · r · dr - - - ( 3 ) ;
By above-mentioned three expression formulas, the relational expression that obtains respectively between each zone radius and the emergent light angle is as follows:
r 1 ( i ) = I 0 P 0 · sin 2 θ 1 ( i ) - - - ( 4 )
r 2 ( j ) = I 0 P 0 · ( sin 2 θ 2 ( j ) - sin 2 θ 1 ) + r 1 2 - - - ( 5 )
r 3 ( k ) = I 0 P 0 · ( sin 2 θ 3 ( k ) - sin 2 θ 2 ) + r 2 2 - - - ( 6 ) ;
Drawn the normal vector of putting on the described free form surface by the law of refraction, utilize this normal vector to obtain the section, by determining that section and any intersection point through inciding the light on the free form surface after the refraction of the lens plane of incidence down obtain the coordinate of putting on the free form surface, obtained down a bit with the straight line at the normal vector place of descending any is crossing by more preceding section, obtain the coordinate of the curve each point of free form surface on coordinate plane by iteration, after the point coordinates that obtains fitted to curve, namely obtain final lens free form surface for 360 ° around the rotation of Z axle.
3. the free-form surface lens for projection-type LED automobile dipped headlight according to claim 2 is characterized in that,
Arrange the free-form surface lens plane of incidence and ellipsoid reflector second focus apart from f=10mm, then the free-form surface lens plane of incidence has according to the law of refraction:
sin θ sin θ ′ = n ′ n - - - ( 7 )
Light incides the free form surface medium from air, and the refractive index of air is n=1, and free-form surface lens uses material PMMA to make refractive index n '=1.4935; θ is light and the Z-direction angle that the angle of incident ray is namely sent from ellipsoid reflector second focus, θ ' namely passes through light and the Z-direction angle that reflects behind the free-form surface lens plane of incidence for the angle of refracted ray, the intersecting point coordinate value of incident ray and the free-form surface lens plane of incidence is (ftan (θ), f), and the slope value of refracted ray is cot (θ '), utilizes point slope form can obtain the equation of refracted ray;
Light reflects again when the exit facet of process free-form surface lens, and the vector form of the law of refraction is expressed as
[ 1 + n 2 - 2 n ( Out → · In → ) ] 1 / 2 · N → = Out → - n · In → - - - ( 8 ) ,
Wherein: n is the free form surface medium refraction index,
Figure FDA00002754549900032
Be the incident ray unit vector,
Figure FDA00002754549900033
Be the emergent ray unit vector,
Figure FDA00002754549900034
Be the unit normal vector of free form surface at the light incidence point;
When definite free form surface shape, at first determine an initial point, this initial point is arranged on the Z axle, numerical values recited be free-form surface lens thickness h and the lens plane of incidence and ellipsoid reflector second focus apart from f with, be initial point coordinate for (0, h+f); If the intersection point A coordinate of incident ray and the free-form surface lens plane of incidence be (x ', f), the point B coordinate that light shines on the free form surface after reflecting through the plane of incidence is (x, z), the point C coordinate that light projects on the illuminated area after reflecting through lens is (r, H), H=25m wherein, r is determined by formula (4), (5), (6) according to law of conservation of energy; So can obtain incident ray
Figure FDA00002754549900035
With emergent ray
Figure FDA00002754549900036
Unit vector, the recycling law of refraction (formula 8) namely obtains the normal vector that B is ordered, thereby determines the section of this point, thus the more following of free form surface determined with any ray intersection through inciding on the free form surface after the plane of incidence refraction down in this section; Obtained down a bit with the straight line at the normal vector place of descending any is crossing by more preceding section, namely obtain the coordinate of each point by the machine iteration; After the point coordinates that obtains fitted to curve, namely obtain final lens free form surface for 360 ° around the rotation of Z axle.
CN2013100217466A 2013-01-21 2013-01-21 Free-form surface lens for projection-type light emitting diode (LED) automobile dipped headlight Pending CN103206668A (en)

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CN107388191A (en) * 2017-07-21 2017-11-24 华南理工大学 Double optical lens with free curved surface for LED automobile dipped headlight
CN107687623A (en) * 2017-07-21 2018-02-13 华南理工大学 Double optical lens with free curved surface for LED car high beam
CN108880473A (en) * 2018-08-28 2018-11-23 天津科技大学 A kind of photovoltaic cell automatic testing equipment
CN106051586B (en) * 2016-08-19 2019-01-11 广东雷腾智能光电有限公司 A kind of headlamp
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CN111443483A (en) * 2020-04-24 2020-07-24 中国科学院云南天文台 Design method of beam shaping structure based on free-form surface lens
CN112946906A (en) * 2021-03-26 2021-06-11 暨南大学 Space light intensity homogenizing system for DMD projection lithography and design method thereof

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Cited By (9)

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Publication number Priority date Publication date Assignee Title
CN106051586B (en) * 2016-08-19 2019-01-11 广东雷腾智能光电有限公司 A kind of headlamp
CN107388191A (en) * 2017-07-21 2017-11-24 华南理工大学 Double optical lens with free curved surface for LED automobile dipped headlight
CN107687623A (en) * 2017-07-21 2018-02-13 华南理工大学 Double optical lens with free curved surface for LED car high beam
CN110469819A (en) * 2018-05-11 2019-11-19 长春海拉车灯有限公司 It is a kind of for the lens of car light, design method and with the car light of the lens
CN110469819B (en) * 2018-05-11 2021-07-09 长春海拉车灯有限公司 Lens for vehicle lamp, design method and vehicle lamp with lens
CN108880473A (en) * 2018-08-28 2018-11-23 天津科技大学 A kind of photovoltaic cell automatic testing equipment
CN108880473B (en) * 2018-08-28 2023-08-11 天津科技大学 Automatic testing device for photovoltaic cells
CN111443483A (en) * 2020-04-24 2020-07-24 中国科学院云南天文台 Design method of beam shaping structure based on free-form surface lens
CN112946906A (en) * 2021-03-26 2021-06-11 暨南大学 Space light intensity homogenizing system for DMD projection lithography and design method thereof

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Application publication date: 20130717